The belts used particularly in wet pressing, drying, calendering, and coating in paper and board machines, especially transfer belts, must be doctored to keep their surfaces clean. The belts in question are, however, relatively soft, so that they are easily damaged, particularly when being doctored with a metal doctor blade. Various plastics are therefore usually used in place of metal in the manufacture of doctor blades. Certain plastics, however, particularly known fibre-reinforced plastics, are too hard for doctoring belts, so that to avoid damage and minimize wear, materials softer than known fibre-reinforced plastics must be used. For example, the edge of a doctor blade made from such a material will impact bluntly against a possible ridge or transverse groove in a belt and thus not damage the belt. The doctor blades generally used to doctor rolls are too hard, and thus are unsuitable for doctoring soft belts.
However, a doctor blade made from a soft material and particularly its edge will disadvantageously flex and creep due to the effect of the loading, temperature, and the duration of the loading. Thus, the doctoring result achieved with such a doctor is poor.